If 2 pounds of grapes cost $6, then one pound of grapes would be $3, because 6 divided by 2 (because there is two pounds) would equal 3. 5 pounds of grapes would cost $15 because 3+3+3+3+3 (or 5 x 3) is equal to 15.
if we take the total cost of the grapes, and divide by the number of pounds of grapes we can conclude that each pound of grapes costs $3. so 5 pounds of grapes multiplied by $3 per pound, gives us $15 for 5 pounds of grapes.
